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PRINCIPLES OF PLANT-TERATOLOGY. 



those rare phenomena in which the surface-area of the 

 shoot becomes reduced, representing, in one sense, the 

 opposite of the fasciated condition. 



Suppression. 



1. Of the Main Axis. — The converse condition to 

 that of proliferation of the main axis, viz., where it 

 has become shortened or suppressed, is, for reasons 

 which will be mentioned later, a rare phenomenon. 

 For instance, Fermond describes specimens of the 

 nipplewort (Lapsana communis) in which the axis 

 was hypertrophied, i. e. much thickened, and, corre- 

 lated doubtless therewith, much shortened owing to 

 the internodes between the foliage-leaves being greatly 

 reduced, so that these leaves came to be arranged six 

 to seven in a false whorl. He also mentions a similar 

 case in the evening primrose (CEnotJiera biennis). 



This same phenomenon (so far as regards the false 

 whorls formed by suppression of internodes) occurs 

 as a perfectly normal thing in many species of Lilium. 



The abnormal maize-plant described by Lcesener is 

 interesting; the stem was exceptionally short and 

 thick-set, and the leaves occurred close together in 

 four decussate rows instead of the normal two rows, 

 a direct result probably of the extreme shortening of 

 the internodes, when, to avoid too great overcrowding 

 of the closely-contiguous leaves one above the other, 

 they became rearranged, as above described, according 

 to the opposite-decussate type of phyllotaxis. 



James cites a depauperised plant of Riidbeclcia 

 hirta, which, in place of an elongated leafy stem, 

 exhibited, owing to extreme and general internode- 

 extinction, merely a basal rosette of foliage-leaves 

 from which arose a leafless one-flowered scape. 

 Again, the counterpart of this phenomenon occurs 

 normally in the same order. In most species of 

 thistle (Cardmis) the flower-heads are formed on tall 

 leafy shoots, but in G. acavlis the main axis of the 



